Bug in VBA function DateDiff

[mikerickson]

This is about the VBA function DateDiff, not the worksheet function DATEDIF.

I've recently found that DateDiff("d", "1/7/1900", "1/8/1900") returns 0 instead of the expected 1.
And there are 3 other dates that have a 0 DateDiff from the next day, 5/6/1900, 6/4/1922, 9/16/1989

This bug also effects the results of date ranges than include those dates.
Is this a known bug?

Thank you for reading.

 

[Leo Skywalker]

According to MS, it is not related to the 1900-1904 Date Systems, and since Mike is able to use the year 1900, it's indeed using 1900 Date system, otherwise he would get a numeric error.

Date Systems
Date Systems 2

 

[Rick Rothstein]

According to MS, it is not related to the 1900-1904 Date Systems, and since Mike is able to use the year 1900, it's indeed using 1900 Date system, otherwise he would get a numeric error.

Date Systems
Date Systems 2

Another reason it cannot be related to the 1900-1904 Date Systems is because Mike is doing this in VBA... there is only one date system there and it is not bound by 1900 or 1904 (those are Excel worksheet systems). It would seem like this is a bug in the Mac version of VBA's DateDiff function.

 

[mikerickson]

That difference has been changed for the last couple of versions of Mac Excel. My version of Excel uses 1900 dates by default.